Railway-traffic-controlling system



April 23, 1929. A. v. '1'. DAY

RAILWAY TRAFFIC CQNTROLLIK:A SYSTEM www mw Patented Apr. 23,1929. i i I 1,710,496 .i UNITED STATES PATENT OFFICE.

'ALBERT V. T. DAY, OF NEW ROCHELLE, NEW YORK, ASSIG-NOR, BY MESNE ASSIGN- MENTS, TO THE-UNION SWITCH' AND SIGNAL COMPANY, OF SWISSVALE, :PENN- SYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY-TRAFFIC-GONTROLLING SYSTEM.

Application filed October 18, 1916. Serial No. 126,240.

This invention is an automatic traiiic-concuits of these secondaries left open, so that 55 trolling system for railways, designed toconthe tuning condensers 18EL and 18b may be trol signaling and braking means or equivaadjusted for very eiicient syntonic resonance lent means carried on a railway train or vewith their respective transformer primaries hicle, in response to control eiit'ected from an 19a and 19b in response to the currents of extraneous point, for example by the pres- 100 cycles and 150 cycles respectively. 60 ence of a second train or vehicle on the same Since the audion systems are the same for track in advance. In the accompanying both frequencies, the system for the 100-cycle drawings, Figure 1 illustrates one embodicurrent maybe described as typical. The secment of the invention, and modifications are ondary or plate circuit of the audion 24a inshown in Figures 2, 3, 4 and 5. cludes the usual battery 31a in series with the 65 In the system here shown, an alternating telephonie amplifier magnets 33El and 34a l current 25-c-ycle traction generator 3 is which are shunted by the tuning condenser grounded to both track rails through an 32 adjusted for resonance with the magnets 15 impedance cross-bond 2, and feeds a transin syntonic response yto 100-cycle E. M. F.

mission line 5 extending along the railway fluctuations in the plate circuit. The tele- 70 and supplying power to drive the traction phonic magnets act simul-taneously in oppomotors such as 9 on the train 10, and also site directions on their respective diaphragms power to drive the synchronous rotary conwhich carry microphone discelectrodes Verters 11, 12b, 13a, 149 whose generator spaced on opposite sides of acommon middle I4windings are connected across the track rails stationary electrode 35a so as to form there- 75 at intervals and deliver thereto currents of with 'two granular microphone cells which- 100 cycles and -150 cycles at alternate sucare connected in parallel in the circuit of the cessive points. Preferably the various genbattery 45a including the primary side of a erator windings of the same frequency will set of ampliiiers 36 adapted to amplify the be connected to the rails in the same instanenergy of the 100-cycle current undulations 30 taneous sign, i. c they willv all simultaneousand deliver a 100-cycle current of greater enly deliver positive polarity to the same rail ergy to the circuit including the relay magand negative polarity to the opposite-rail. net 38 and tuning condenser 37a adjusted The train 10 moves leftward and carries for syntonic resonance at 100 cycles. Since in frontacoil 16 disposed in electro-magnetic the vibration of the railway vehicle will 85 inductive relation to the track rails. Cur tend to move both diaphrams of the telerents of 150 and 100 cycles from the two rophonic amplifier simultaneously, in the same tary converters ahead, iow rearward through direction it will increase the microphonic the track rails and the wheels and axlesof resistance of one cell while simultaneously the train 10, 'thus inducing in the train coil decreasing the resistance of the parallel cell, 90 16 a composite E. M. F. including composo that the joint resistance of both cells in nents of both frequencies. The terminals of their battery circuit will not be greatly afthe train coil 16 are connected to the leads fected by such vibration; whereas the tele- 40 17 across which' are bridged the transformer phonic magnets 33 and 34a in response to primaries 19a and 19h, each in series with the 100-cycle current undulations will move 95 a tuning 'condenser 18a or 18b respectively. their diaphragms simultaneously toward and The secondaries 21a and 211J of the trans from their common middle microphone elecformers are connected respectively in the trode a vso as to simultaneously increase grid circuits of the 'audions 24a and 24" in and decrease the resistance of both microseries with potentiometers 22 and 22 respecphone cells to effect their maximum joint-re- 100 tively, which are adapted to adjust the Imean sistance variation in the circuit of the. bat' potentials of the grids 26 and 26h for the -tery 45, best amplifying effects. Although the trans- "W hen the relay magnets 38ct and'38b are 50 yformers 20ci and 20: constitute close couboth simultaneously energized by 100-cycle "plings, the frequencies employed are so low and 15G-cycle currents respectively, they will 105 that t he grid capacities in series with the simultaneously close their respective contransformer secondaries will be small enough tacts 39 and 39b so as to complete the cirto approximate the effects of having the circuit of the battery 40 including these contacts in series with each other and the signal lamp 41 and magnet 42 controlling the l brake valve 43. vManifestly this train-conicient to include the connecting points of at least two of the successive rotary converters which feed the-100-cycle and 150-cycle currents to the track rails at alternatively successive points.

If desired, a movable visual signal may be controlled by the local circuit of the battery 40, for instance such an indicator as 64 actuated by the valve-controlling magnet 42; and an'audible signal may also be included in vthis circuit, as at 67. Also the amplified 10U-cycle and 15G-cycle currents may directly energize tralic-controlling devices, for example the disc indicators 65a and 65b actuated by the magnets 38Zt and 38b respectively, or the signal lamps 662-* and 66b inserted respectively in, the circuits of these magnets.

In lieu o the inductive coil 16, any other suitable scheme may be employed to derive controlling current from the track rails. For instance, as shown in Figure 2, the leads 17 to the train-control apparatus may derive current from a coil 57 wound on a hollowcylindrical laminated magnetic core 58 surrounding the front axle of the train or car, and the impedance of one or more of the fol- ,lowing axles may be increased by similar magnetic cores as at 55, to cause a greater proportion of the track current to flow through the first axle for inducing controlling current in the coil 57. Or, as shown, in Figure 3, the apparatus leads 17 may bey conneeted with contact shoes or brushes 54 bearing on the track rails at points as far as practicable in advance of the front wheels of the train; and as shown in this same figure, the apparatus leads 17 may be connected also with brushes 56 bearing on the treads of the front wheels; and one or more of the foremost axles may be surrounded with the impedante cores 55, to shunt as much current as practicable into the train-control apparatus. Or, as shown in Figure 4, the apparatus leads 17 may receive current from brushes 6l bearing on the front wheel treads 63v which are insulated from the wheel hubs and axle byinterposed insulative linings 62 which may also be applied in the wheels of one or more following axles.

For 'simplicity of representation, the system of Figure 1 has been limited to only two b frequencies of train-controlling current, but in lieu thereof, the rotary converters at e, f, g and z', couldall deliver different frequencies, their sequence being repeated indefinitely throughout successive sections of the track; or a sequence of sources including .many more than four successive frequencies could be employed.

ployed, they may selectively control as many respective translative devices or relays whose ncontrolled contacts are indicated at 39a, 39",

39c and 39d in Figure 5.

In the device of Figure 5, the vertical guide tube 5l has an integral flange at its lower end by which it may be mounted on a suitable base. Into the upper end of this tube is inserted a hollow-cylindrical cupform magnetic sheath 47a, .with its open end downward, and a solenoid 46a is secured in the sheath. A solenoid core 48a slides vertically in the solenoid and is connected at its lower end with the upper closed end of a second magnetic solenoid sheath 47b which slides in the guide tube 51 and contains the solenoid 46b fixed within the sheath. A stud 59a projects radially from the solenoid sheath 47a into a longitudinal groove 60a in in the core 48a to limit the withdrawal of the core from the sheath so that it cannot pass beyond the effectual attractive effort of the solenoid 46a. A core 48b likewise co-acts with the solenoid 46b and is likewise limited in its withdrawal movement by a stud projecting from the sheath 47h, into a groove in the core. The core 48b carries a depending solenoid sheath 47 and enclosed solenoid 46c similarly co-acting with still another core 48 which likewise suspends still another sheath 47d and its solenoid 46d co-aeting in the same way with the lowermost core 48d which carries at its lower end a horizontal crossbar 49, 50, projecting in both directions through opposite longitudinal slots in the guide tube 51.

Thus the solenoid sheaths and cores constitute a vertical chain slidably suspended in the guide tube so as to be shortened by the movement of each core into its solenoid when the solenoid is energized. Therefore, the elevation of the lowest core 48d and its cross-bar will always be the sum of theA movements. of the several cores into their respective solenoids, which will always be proportional to the number of solenoids simultaneously energized, providing such movements of the several cores are all equal.

One terminal of each solenoid is grounded on its sheath which makes conductive contact, with the guide tube connected with one pole of the battery 53. The other terminal of each solenoid is connected with the opposite battery pole through a respective one of the contacts39, 39", 39" and 39d controlled y respective track-current frequencies, so that each solenoid will be energized when its respective current-frequency is received from the track rails, wherefore the elevation of the lowest solenoid core and its cross-bar will be proportionate to the number of trackcurrent frequencies effectually received by a train, so as to vary with the clear distance of track extending in advance of the train.

of a warning signal or train-braking or retarding means.

The functions of the amplifying means of this invention must not be confounded with the functions of ordinary circuit-closing relays which serve merely to close and open a local circuit in response to the rise and fall of a controlling current and which are not amplifying devices in vthe proper sense designating apparatus for producingl an amplified current which varies with the strength of a controlling current. The amplifying means employed in the present invention are in the nature of telephonie amplifiers. which repeat minute" currents and current undulations with a given factor of amplification so that' the repeated current of greater power will derive its characteristics from the controlling current. Since this is accomplished by a micro-variable influence of the amplifying means on the amplified current in a sensitive response to all minute variations in the controlling current, the means thus qualified may be termed generically micro-responsive or micro-variant amplifiers. The comparative action of the micro-variant amplifiers and other relays or translating means not thus qualified, must be understood in order to appreciate the philosophy of the present invention and its relation to the art. It may be safely stated-as a generality that all means of deriving current from track rails short-circuited by a railway train or vehicle, for controlling apparatus on the train or vehicle, are essentially inefficient in energy transmission. But all electro-transf lative devices which embody the safety function`v in a protective system, must be controlled by sufficient energy to insure very.

of action. For instance, a warning indicator or a relay which is moved to a fixed clear position by controlling current, must be actuated by some very positive retrac-tive force to move from clear great certainty position when that controlling current is discontinued or reduced by a given margin,

else the device might stick and remain clear when it should move to perform a protective function essential to safety. Therefore the controlling current which actuates the device must have sufficient energy to overcome .this very positive retractive force While moving the device to its clear position and there retaining-it.

the device is a signal lamp to be directly actuated by energy derived from the trac rails, obviously it must receive a very considerable amount of energy to effectually from a short-circuited rail-circuit to apparatus on the train, unless an excessive current be employed inthe rail circuit.

Through the agency of the micro-responsive or micro-variant amplifying means, a relatively Weak short-circuited rail circuit may efficiently and reliably govern a traffic-controlling apparatus carried on a railway train or vehicle. An amplifying device of this character may have a given factor of amplification which Will express the ratio of its output energy to its controlling energy, and when a number of such amplifiers are employed together in sequence, as the amplifiers 24a and 33a, 34 and 36a, their joint amplifying factor their several factors may easily equal 1,000,000.

Manifcstly selectivit the broad purview l o when required it suit-able means applied at any suitable point in the course of transmission. For example, in the illustrated embodiment the selectivity condensers -182L and 32EL and selectivity couldbe effected solely in the controlled circuit of the amplifying means 36a. In fthis instance, the micro-vibrant amplifiers could readily be made to faithfully reproduce the frequency or other controlling-current characteristics relied upon for selectivity. Or one or more pre-amplifiers of micro-variant character may be located in the box 69 and introduced by the is not essential in the invention, but

switches 68 into thecourse of controllingrelay could be made safely responsive to anexceedingly minute current, yet it could not reproduce in its controlled circuit the characteristics thereof which must be relied on for selectivity.

With regard for the effect of a selectivity expedient such as resonance in the transmission of tvvo given currents of respective given frequencies, the ratio of the transmission-efficiency for the preferred current to the transmission-efficiency current, may be termed the modulus of selectivity or the selective modulus. In the employment of successive selective means in sequence as in the illustrated embodiment, their resultant or joint selective,` modulus which is the product of their several. moduli, may readily be made equal to 1,000,000, or more, depending on the relation of frequencies and the characteristics of the seleccontrolling current in the which is the product of' may be effected by any' 'might be omitted for tlie rejected i such relation tive means. Hence the frequencies of the traffic-controlling currents may be chosen in to one another and to the frequencyof traction current and other foreign currents, that any given traffic-controlling current may be enormously amplified in its ultimate application to the traffic-controlling device which it governs, WithoutY ap lying to that particular device any apprecialile measure of any current foreign to its proper control; and this remains not only a mathematical possibility but a wholly feasible undertaking even. when the said foreign current vastly exceeds the proper controlling current both in the rail circuit and in the train coil or equivalent derivative circuit. Since the selective modulus of the selectivity means associated with each amplfying device may greatly exceed the amplifying factor of that device, the current foreign to any particular traffic-controlling.device may be successively diminished while the proper traffic-control ing current is repeatedly `amplified in transmission through successive amplifying devices, so that foreign currents Ina be sifted out to any desired extent.

n virtue of the foregoing characteristics of the ap aratus, the traffic-controlling means on t e train or vehicle can be controlled with superlative reliability by a current in the track rails of no greater strength than Would ordinarily be required to control a relay directly included in series in the rail circuit. Indeed, by employing amplifying means having a sufficient factor of amplification, the control may be effected with a current in the rails having only a minute fraction of the strength necessary for the direct actuation of an ordinal' relay, thus effecting a very great economy 1n rail-circuit power.

Although the traffic-controlling means on v the tra-in or vehicle may be thus governed by a relatively minute controlling current in the rail circuit, it'must be understood that this practice does not involve any hazard of false actuation by that measure of controlling current which, theoretically, must be transmitted to the controlled train or vehicle from an adjacent track-source even when the intervening rails are shunted by a preceeding train. The amplifying means may be designed for a certain amplifying factor which will remain constant so long as the amplifiers are maintained in statu quo and which cannot in any event be spontaneousrly or accidentally increased. Hence the strength of the amplified controlling current which ultimately actuates the governing member of the traffic-controlling means, Will be subject to corresponding strength modulations in response to every currentstrength variation in the rails, so that when the rail-circuit current is reduced to a given percentage by presence of a preceeding train the said amplified actuating current Will be correspondingly reduced. Therefore the trahie-controlling device may be adjusted to assume its Warning or danger or retarding function in response to any given percentage decrement of controlling current 1n the rail circuit which may be determined by considerations of safety or prescribed by engineering conventions. Obviously the percentage decrement in current strength in the rail circuit effected by short-circuiting action of a train or vehicle, will be the same whether a Weak or a strong source of current be employed to feed the rails.

The amplifying means may be `of any suitable micro-responsive or micro-variant species, many of which are familiar in telephony. For instance, any number and species of such generic means may be included in amplifying sequence in 36a and 36b of the illustrated embodiment, and any suitable selectivity means may be.

employed therewith. Various species ofl micro-responsive amplifiers can be made ex'- ceedingly rugged and durable, but it should be noted that the most delicate species could be employed Without an hazard of dangerous failure, so long as t e trame-controlling means is selectively responsive solely to a certain current characteristic which can be delivered by the amplifying means only when derived from the rail circuit. For example, if a very delicate microphonic amplifier were excited by mechanical vibrations to deliver current to the traffic-controlling means, there would be no effective correspondence between this false current and the proper controlling current in the rails. i

Manifestly, all the track sources of a given frequency could be omitted from the system of Figure'l together with all the train apparatus responsive to that frequency, and the remaining train apparatus responsive to current from the remaining track sources Would still be operative to show a clear track extending in advance of the train as far as the rst track source ahead of the train position. The invention in its broad aspect is not limited to the employmcnt of controlling currents of different characters.

the amplifier boxes llO Many different adaptations of the inventhe character in which the track rails com-.

municate controlling current to the governing means, comprising apparatus on a moving train continuously governed by traftic conditions ahead to impose a permissible speed indication ory limit which is a functiony of the clear headway.

2. A railway signaling system comprising track rails, means for supplying alternating signaling current thereto at intervals, adjacent sources differing in frequency, a vehicle, a circuit thereon receiving signaling currents from the currents thus supplied to the rails, means on thel vehicle for amplifying the currents received in said circuit, devices on the vehicle, one for each frequency, means for supplying to each device current from said amplifying means of one only of said frequencies, and vehicle governing means on the vehicle controlled by said devices'. n

3. In a railway signal system, a trafiic rail adapted to carry currents of different frequencies, signal circuits in a railway car each responsive to one of said currents of Y s n different frequencies, means for lnterconfor indicating a track condition, and means necting said signal circuits with .a main signal circuit, means associated with each of said signal circuits and including a reactive circuit tuned to the frequency to which the corresponding signal circuit is responsive to permit the passage only of the current of 4 said 'last frequency, and a frequencyresponsive relay in each of said signal circuits.

4. In a railwaysignal system, a transmission circuit adapted to carry currents of different frequencies, signal circuits in a railway car each responsive to one of said currents of different frequencies, means for iii- 'terconnecting said signal circuits with said main signal circuit, means associated with each of said signal circuits and including a reactive circuit timed -to the frequency to which the corresponding signal circuit is ren sponsive t-o permit the passage only of the currentof said .last frequency, means for intensifying the effects of said currents in each of said signal circuits, and a device in each of said signal circuits selectively responsive to current of the corresponding frequency.

5. In a railway locomotive, a signal circuit, means for communicating currents of different frequencies from a main track cir/ cuit to ysaid signalv circuit, means in said' signal circuit responsive to one frequency in said circuit responsive to another frequency for controlling other traffic controlling means.

6. In a railway signal system, in combination, a plurality of circuit-s for carrying currents of different frequencies, indicating devices, one responsive to each of said currents, means actuated by the presence of a train for affecting one of said circuits, and other means similarly actuated for affecting other said circuits.

7. In an automatic train control or cab signalling system, in combination: a railway vehicle; a stationary conductor extending along the path of movement of the ve-` hicle; traic Avcontrolled means for supplying a periodic signaling current to said conductor; a coil on the vehicle arranged in inductive relation with said conductor; a circuit on the vehicle includin said coil and tuned to the frequency of said signaling current; an electrical amplifying device included in said circuit; a relay effected onl by current of the frequency of said signa ing current and controlled bv the current supplied from said amplifying device; and train control apparatus on tne vehicle controlled by said relay.

8. In a railway signal system, a traic rail circuit adapted to carry currents of different frequencies, signal circuits in a railway car each responsive to one of said currents of different frequencies, means for interconnecting said signal circuits with said main signal circuit, means associated with each of said signal circuits and including a reactive circuit timed to the frequencyv to which the corresponding signal circuit is responsive to permit the passage only of the current of said last frequency, frequencyresponsive devices each .associated with one ofy said signal circuits and auxiliary circuits for operating indicating devices and for controllingthe further movement of said car, said circuits being controlled b'y said devices.

9. In a railway signal system, a transmission circiut normally carrying currents at different frequencies, signal circuits in a car each of which is adapted to respond to one of said frequencies, means for communicating said currentsfrom said main circuit to said signal circuits, and means affected by a train preceding said car for preventing said communication of current.

10. In a railway signal system, in combination, a plurality of circuits for carrying currents of different frequencies, indicating devices, one responsive to each of said currents, means actuated by the presence of a train for affecting one of said circuits, and other means similarly actuated for affecting other said circuits.

1l. In combination, a stretch of railway track, railway vehicles thereon, a plurality of sources of signaling current differing in llO said track rails, there being one such means for each frequency of signaling current, and vehicle-governing apparatus on the vehicle responsive to the number of such means energized at a time. v

13. In combination, a stretch of railway track, means for supplying alternating signaling currents thereto, the adjacent sources differing in frequency, deviceson a vehicle selectively responsive tosaid currents of different frequencies, and vehicle governing means 011 the vehicle controlled by said devices.

14. In combination, a stretch of railway track, means for supplying alternating signaling current thereto, adjacent sources differing in frequency, devices on a vehicle selectively responsive to said currents of different frequencies, speed responsive apparatus on said vehicle, and vehicle governing means on the vehicle controlled jointly by said devices and said apparatus.

15. A railway signaling system comprising electrically continuous track rails, means for supplying alternating signaling current thereto at intervals, adjacent sources differing in frequency, a vehicle, a circuit thereon receiving signaling currentsfrom the currents thus supplied to the rails, means on the vehicle for amplifying the currents received in said circuit, devices on the vehicle supplied with currents from said amplifying means and selectively responsive to the currents of different frequencies supplied to the track rails, and vehicle governing means on the vehicle controlled by said devices.

1G. The method of controlling railway traffic which consists in producing inV the track rails currents of different frequencies, employing said rail currents to control amplifying means carried on a railway vehicle and selectively responsive to each frequency, and employing the output energy of said amplifying means to govern trafficcontrolling means on the vehicle. 17. The method of controlling railway traffic which consists in producing in the track rails currents of different frequencies, employing said railfcurrents to energize respectively tuned circuits controlling the input to amplifying means carried on a railway vehicle, and employing the output energy of said amplifying means to govern traffic-controlling means on said vehicle.

18. The method of governing railway tiaflic which consists in producing in the track rails a flow of current having a periodic variation, deriving therefrom E. M. F. available on a railway vehicle, and employing said E. M. F. on the vehicle jointly with the speed of the vehicle to govern traffic-controlling means carried on the vehicle.

19. The method of governing railway traffic which consists in producing in the track rails currents of different frequencies, deriving therefrom respective E. M. F.

fluctuations available on a railway vehicle,-

and controlling the movement of the vehicle jointly by said E. M. F. fluctuations and speed-responsive means governed by the speed of the vehicle'.

20. A railway traffic governing system comprising track rails, means for supplying alternating signaling current thereto, a vehicle, a circuit on said vehicle receiving energy from the rails and tuned to resonance at the frequency of the signaling current, a second circuit on said vehicle including a local source of current, an amplifier on the vehicle for causing yariations of the current in said second circuit corresponding to variations of the' potential in the first circuit, and vehicle governing means controlled by the current in said second circuit.

21,. Iailway traffic controlling apparatus,

comprising track .rails supplied at'times lwith an alternating signaling current, a vehicle, a circuit on said vehicle including a coil in inductive relation to a track rail and a capacity device for at least partially Abalancing' the inductive react-ance of the circuit, amplifying means controlled by said circuit, and governing means on the vehicle controlled by said amplifying means.

22. Railway trafic controlling apparatus comprising track rails supplied at times with an alternating signaling current, a vehicle, a circuit on said vehicle including a coil in inductive relation to a track rail and a capacity device for reducing the reactance of said circuit, amplifyingmeans controlled by said circuit, and governing means on the vehicle controlled by said amplifying means.

23. In an automatic train control or cab signaling system, in combination: a railway vehicle; a stationary conductor extending along the path of movement of the vehicle; traffic controlled means for supplying a periodic signaling current to said conducllO tor; a coil on the vehicle arranged in inductive relation with said conductor; a circuit on the vehicle including said coil and a capacity device for reducing the reactance of the circuit, an electrical amplifying device included in said circuit; a relay affected only by current of the frequency of' and cont-rolled by.

said signaling current the current supplied from said amplifying device; and train control apparatus on the vehicle controlled by said relay.

24. In a railway signaling system, in combination: a railway track; means nullified by the presence of a train on a prede-- termined portion of the track for normally supplying periodic signaling current to the track rails of the track for a predetermined distance in the rear; a vehicle adapted to travel over the track; a circuit on the vehicle having a portion thereof disposed rent of a predetermined frequency, a train carried circuit arranged in inductive relation with the trackway circuit and including a .for impressing capacity device for reducing the reactance of the circuit, an amplifying device responsive to the flow of current in a train carried circuit, and a normally energized relay governed by the current supplied from said amplifying device and affected onlyl by current of said predetermined frequency.

26. In combination, a railway track, means two alternating signaling a vehicleprovided with receiving alternating currents in the track,

currents thereon, means for inductively potentials due to said two amplifiers on spectively by the two potentials induced in said receiving means, and speed governing apparatus for said vehicle controlled jointly by said amplifiers.

27. In combination, a railway vehicle, two electron tube amplifiers thereon each having a heated filament and a rid and a plate, a grid circuit and a plate circuit for each amplifier, governing apparatus for the vehicle controlled jointly by said two plate circuits, and means located partly on the vehicle and partly in the trackway for supplying alternating voltages to said two grid circuits, respectively.

28. In combination, a railway vehicle, two electron tube amplifiers thereon each having a heated filament and a grid and a plate, a grid circuit for each amplifier', means located partly on the vehicle and partly in the trackway for supplying one alternating'potential to the grid circuit for one amplifier and another alternating potential to the grid circuit for the -other amplifier, a plate circuit for cach amplifier including a source of direct current, and apparatus controlled jointly by said two plate circuits and responsive to variations in flowing therein for governing the vehicle.

29. In combination, a railway vehicle, two electron tube amplifiers thereon each having a heated filament and a grid and a plate, means located partly von the vehicle and partly in the trackway for creating an alter- 'nating potential between the filament and grid of one amplifier and an alternating potential between the filament and grid of the other amplifier, a plate circuit for each amplifier including a source of direct current,

Imeans located part said vehicle controlled retrolled respectively by the strength of the currents and apparatus controlled jointly by said two plate circuits and responsive to variations in the strength of the currents flowing therein for governing the vehicle.

30. In combination, a railway vehicle, two electron tube amplifiers thereon each having a heated filament and a grid and a plate ly on the vehicle and partly in the trackway for creating an alternating potential between the filament and grid of one amplifier and an alternating potential between the filament and grid of the other amplifier, a plate circuit for each amplifier including a source of direct current, two windings associated with said two plate circuits respectively and each receiving alternating potential due to the potential applied to the grid and filament of the cor-l responding' lamplifierl but ofA increased strength, and governinv apparatus for said vehicle controlled jointly by said two windings.

31. In combination, a railway track, means for impressing two alternating signaling currents thereon, a vehicle provided with means" for inductivel f .receiving alternating potentials due to sai currents in thetrack,

two amplifiers bn said vehicle controlled respectively by the two potentials induced in said receiving means, two windings on the vehicle associated with said two amplifiers respectively and each receiving an alternating potential due to the potential applied to the corresponding amplifier but of increased strength, and apparatus controlled jointly by said two windings for governing the vehicle. l

32. In combination, a railway track, means for impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receiving alternating potentials due to said currents in the track, two amplifiers on said vehicle conthe two potentials induced in said receiving means, two windings on the vehicle associated with said two amplifiers respectively and each receiving an alternating potential due to the potential applied to the corresponding amplifier but of increased strength, and brake governing apparatus on the vehicle controlled jointly by said two windings and by the speed of the vehicle.y

33. In combination, a railway track, means for impressing two alternating signaling currents thereon, a vehicle provided with means for' inductively receiving alterlnating potentials due to said currents in the track, two amplifiers yon said vehicle controlled respectively by the two potentials induced in said receiving means, and brake apparatus on the vehicle controlled jointly by said two amplifiers and by the speed of the vehicle.

34. In combination, a railway vehicle, two

electron tube amplifiers thereon each having a heated filament and a grid and a plate, means located partly on the vehicle and partly in the trackway for creating an alternating potential -between the filament and grid of .one amplifier and an alternating potential between the filament andgrid of l current of train carried circuit arranged in inductive the other amplifier, amplifier including rent,two` windings associated withsaidtwo platecircuits respectively and each receiving'ajlternating potential due to the potentials'applied to the grid and filament of thel associated amplifier but of increased strength and brake governing apparatus on the vehiclecontrolled jointly by said two windings and by the speed of the vehicle.

35. The method of governing railway traffic which consists in supplying two alternating currents tothe track rails, creating'correspondingvoltages on a vehicle by induction, amplifying said voltages, and controlling a vehicle -governing mechanism by said amplified voltages. I

36.The method of' governing .traiiic which consists in supplying twol ala plate circuit for each vteriiating Vcurrents to the track rails, creating correspondin volta-ges on a vehicle'by induction, ampli ying each induced voltage separately, and controlling a unitary vehicle governing mechanism jointly by said amplified volta es.

37. The met od of governing railway traffic which consistsl in supplying two alternating currents to the track rails, creating corresponding voltages on a vehicle by induction, and governing the vehicle by said induced voltages and by the speed' of the vehicle.

38. A normally active impulse transmitting system for automatic cab signaling or train control systems comprising a trackway circuit normally energized with periodic a predetermined frequency, a

relation with the trackway -circuit and tuned to the frequency of the current therein, an amplifying device responsive to the ow of current in a train carried circuit, and a normally energized relay governed by the current supplied from said amplifying current of said predetermined frequency.

89. A railway signaling system comprising track rails, means or impressing thereon signaling currents of two frequencies, and. signaling means controlled by energy received from said track rails and selectively responsive to said two frequencies to give two distinct indications according as one or both frequencies are present and a third indication in the absence of current of either frequency.

40. A railway signaling system/comprising track rails, means for impressing a source of-direct cur-- railway device and affected only by ergy received from said 'track vrails and controlled by enselectively responsive to said two frequenv cies. 41. A railway signalingsystem'comprising track rails, means for impressing thereonsignaling currents differing in frequency, and signaling means controlled by energy received from said track rails and selectively/ responsive vto said frequencies to give a plurality of indications.

42. A railway signaling s stem comprising track rails, means or impressing thereon signaling v'currents of two frequencies, a railway vehicle, two relays thereon controlled yby energy received from the track rails and selectively responsive to said two frequencies, and signaling apparatus on said vehicle controlled by said relays. y 43. A railway signa-ling system comprising track rails, means for impressing thereon signaling currents of two fre uencies, two circuits controlled by energy in said rails and resonant respectively to said two frequencies, and signaling means controlled by said circuits.

44. A railway signaling system comprising track rails, nating signaling current'thereon, a railway vehicle, a circuit thereon arranged to receive energy from the track rails, a second circuit on the vehicle resonant to current of said signaling frequency, a current amplifying device inter osed between said two resonant circuits, and) vehicle governing means controlled by said second resonant circuit.

45.' A railway signaling system comprising track rails, means for impressing alternating signaling current thereon, a railway vehicle, a circuit thereon arranged to receive energy from the track rails, a vacuum tube amplifier on the vehicle comprising a filament continuously energized from a source of direct current, a plate, and av grid interposed between the filament and the'plate,

means for impressing alterino'.

means for connecting said filament and said 1 grid with said circuit so that alternating currents in the circuit produce an alternating difference `of potential between the filament and the grid, a second circuit connected with said filament and said plate and resonant to current of said signaling frequency, and vehicle governing trolled by said second circuit.

46. A railway signaling system comprising track rails, means nating signaling current thereon, a railway Vehicle, a circuit thereon arranged to receive energy from the track rails and resonant to current of said signaling frequency, vehimeans C011- v for impressing altercle governing means on said vehicle, and

amplifying means on the vehicle between said resonant circuit and said governing means for enabling the governing means Y the frequency tube amplifier having a heated filament and,

a grid and a plate, a gridcircuit for said amplifier, aecircuit on said vehicle inductively related to a track rail for supplying voltage to said grid circuit of the same frequency-as that of the alternating signaling current in the track rails, a plate circuit for said amplifier including a source of direct current, and means associated with saidV plate circuit and responsive to variations in the strength of the current flowing thereln `for governing said vehicle.

48. Railway trafiic controlling apparatus comprising track rails, a source of alternatsignaling current connected thereto, a railway vehicle provided with an electron tube amplifier having a heated filament and a grid and a plate, a grid circuit for said amplifier, means including a winding in inductive relation to a track rail for energizing said grid circuit, a plate circuit for sai amplifier including'a source of direct current, and means associated with said plate circuit and responsive to variations in the strength of the current flowin-g therein for governing said vehicle.

49. Railway traflic controlling apparatus comprising track rails, means for supplying alternating signaling current to said rails, a vehicle, a circuit on said vehicle tuned to of said signaling current and including a winding in inductive relation to a track rail, an electron tube amplifier on said vehicle, a grid circuit for said amplifier energized by said tuned circuit, a plate circuit for said amplifier including a source b v of direct current, and means associated with said plate circuit andV responsive to variations in the strength of the current flowing therein for governing said vehicle.-

50. Railway traffic controlling apparatus comprising track rails, a source of alternating signaling current connected thereto, la railway vehicle provided with an electron tube amplifier having a heated filament and a grid and a plate, a grid circuit for said amplifier, means including a winding in vin'- ductive relation to a track rail for energizing said grid circuit, a plate circuit for said amplifier including a source of direct current, and means associated with said plate circuit and responsive to variations in the strength of the current flowing therein for controlling the brakes of said vehicle.

51. In combination, a railway vehicle, an electron tube amplifier thereon having a heated filament and a grid and a plate, a plate circuit for said amplifier includingr a source of direct current, means controlled by said plate circuit for governing lsaid vei hicle, and hicle and partly in the trackway for creating an alternating difference of potential between the filament and grid of said amplifier.

electron tube amplifier thereon having va heated filament anda grid and a plate, a

plate circuit for said amplifier including a source of direct current, means controlled 52. In pmbination, a railway vehicle, anV

means located partly on the vebysaid plate circuit for governing said vehicle, a grid circuit for said amplifier, and

means located in the trackway and con trolledby traffic conditions in advance of the vehicle for creating an alternating'dif-,-

ference of potential in said grid circuit.'

53. Railway traflic controllin .apparatus comprising track rails, means or impressing thereon two alternating signaling currents, a vehicle, provided with means for inductively receiving voltages due to said currents, amplifying means' on said vehicle controlled by the voltages impressed on said receiving means, andspeed governing ap- '.paratus on said vehicle controlled by said d amplifying means.

54. Railway traffic controlling apparatus comprising track rails, means for impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receiving voltages due to said currents, and apparatus on said vehicle controlled by said voltages for automatically governing the speed of the vehicle.

55. Railway traffic controlling apparatus comprising track rails, means for impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receiving voltages dueto said currents, and apparatus controlled by said voltages for Governing the brakes of said vehicle.

56. Railway traffic controlling apparatus comprising track rails, means for impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receiving voltages due to said currents, and apparatus controlled jointly by the speed of the vehicle and by said voltages for governing said vehicle. y.

57. Railway traflic controlling apparatus comprising track rails, means for impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receivingvoltages due to said currents, two windings on said vehicle supplied with currents corresponding to said induced voltages, and apparatus controlled jointl by said windings for governing the vehic e.

'58. Railway traffic controlling `apparatus comprising track rails, means'for impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receiving voltages due to said currents, two wlndmgs on sa1d vehicle supplied with curc rents corresponding to said induced voltages,

and governing apparatus on said vehicle controlled jointly by said windings and by the speed of the vehicle.

59. Railway traffic controlling apparatus comprising track rails, means for impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receiving voltages due to said currents, two windings on said vehicle,y means interposed between said receiving means and said windings for supplying the windings with alternating potentials corresponding to said induced potentials but of greater am litude, and apparatus controlled by said windings for governing the vehicle. y

60. Railway traffic controlling apparatus comprising track rails, means for-impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receiving voltages due to said currents, amplifying means on said vehicle controlled by the voltages impressed on said receiving means, two windings located on said vehicle and supplied by said amplifying means with alternating potentials corresponding to the voltages impressed on said receiving means but of greater amplitude, and apparatus controlled jointly by said windings for governing the vehicle.

61. Railwayl traffic controlling apparatus comprising track rails, means for impressing two alternating signaling currents thereon,

la vehicle provided with means for inductively receiving voltages due to said currents, amplifying means on said vehicle controlled by the .voltages impressed on said receiving means, two windings located on said vehicle and supplied by said .amplifying means with alterna-ting potentials corresponding to the voltages impressed on said receiving means but of greater amplitude, and brake governing apparatus on the vehicle controlled jointly by said two windings and by the fspeed of the vehicle.

62. Railway traffic controlling apparatus comprising track rails, means for impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receiving voltages due to said currents, amplifying means on said vehicle controlled by the voltages impressed on said receiving means, two windings located on said vehicle, means interposed between said aniplifying means and said windings for supplying the windings with alternating potentials corresponding to the voltages impressed on said receiving means but of greater amplitude, and apparatus controlled jointly by said windings for governing the vehicle.

63. Railway traffic controlling apparatus comprising track rails, means for impressing two alternating signaling currents thereon, a vehicle provided with means for inductively receiving voltages due to said currents, am-

plifying means onsaid vehicle controlled by the voltages impressed on said receiving means, two windings located on said vehicle, means interposed between said amplifying means and saidwindings for supplying the windings with alternating potentials corre` 64. In combinatiomma railway vehicle, an

electron tube amplifier thereon having a heated filament 'and a grid and a plate, means located partly on the vehicle and partly in the traclcway for creating an alternating difference of potential between the filament and grid of said amplifier, a plate circuit for said amplifier including a source of direct current and a winding, and governing apparatus for said vehicle controlled by said winding.

65. In combination, a railway vehicle, an electron tube amplifier thereon having a heated filament' and a grid and a plate, means located partly on the vehicle and partly in the trackway for creating an'alternating difference of potential between the filament and grid of said amplifier, a plate circuit for said amplifier including a source of direct current and a winding, and brake governing apparatus on `the vehicle controlled jointly by said winding and by the speed of the vehicle.

66. Railway trafiic controlling apparatus comprising .track rails, a source of alternating signaling current connected across said rails, a second trackway circuit includinga second source ofv alternating signaling current, and vehicle carried traffic governing means inductively controlled by the joint action of said trackway currents.

67. In a railway signal system, a traffic rail circuit adapted to carry currents of difference frequencies, signal circuits in a railway car each responsive to one of said currents of different frequencies, means for inter-connecting said signal circuits with said traffic rail circuit, means associated with each of said signal circuits and including a reactive circuit tuned to the frequency `to which the corresponding signal circuit permit the passage only of signaling current, means for communicating.

said signaling current variations from said main circuit to said second signal circuit, and a signal indicating device responsive to -said current variations.

69. In a railway signal system, a transmission circuit adapted to carry signal operating currents of different frequencies.

signal circuits in a railway car,

each of 5 which is adapted to respond to one of said frequencies,v means for communicating said currents from said main circuit to said sig- ALBERT V. T. DAY. 

